Finding, catching and eating it.

Carnivore= animal that eats other animals

Herbivore= animal that eats plants

Omnivore= animal that eats both animals and plants ( humans)

Decomposers consume because that's what their part of the food chain is. They are decomposers because they consume dead and decaying matter. They do not consume because they are decomposers.

Yes. People consume food. You could also say that cars consume gas. Fire consumes oxygen. Consume is a versatile word.

The abstract noun for the verb to consume is consumption.